Audi announced that it will introduce new, lightweight suspension springs made of glass fiber-reinforced polymer (GFRP) on an upper mid-sized model before the end of the year. Our guess is that the vehicle that will receive the new springs is the 2015 Audi A7 although we have to see a confirmation from the German manufacturer.

According to the official press release, the GFRP springs were developed with an Italian supplier and as obvious, they look different than the standard steel springs. First if all, the GFRP are green, while the fiber strand is thicker than the wire of a steel spring.

In addition, the GFRP spring has a lower number of coils and a slightly large overall diameter. Still, the most important thing is that it is 40 percent lighter when compared with the steel springs. For those who don’t know, the steel spring on an upper mid-size model weighs almost 2.7 kg (6.0 lb), while the GFRP spring drops the weight to 1.6 kg (3.5 lb).

This means that the four GFRP springs found on a vehicle reduce the total weight by 4.4 kg (9.7 lb). Audi says that the core of the springs consists of long glass fibers twisted together and impregnated with epoxy resin.

Moreover, a machine wraps the additional fibers around this core at alternating angles of plus and minus 45 degrees to the longitudinal axis. The last step in production is to curing the blank in an oven at temperatures that exceed 100 degrees Celsius.

It took Audi a lot of work just to revise the A7 Sportback five-door coupe, making it more powerful and more appealing. Thanks to new engine configurations and transmissions, as well as headlights, taillights, and infotainment systems, the new A7 Sportback further boosts its charm. As created, the new A7 Sportback offers the functionality of an Avant, the comforts of a sedan as well as the sportiness and emotional appeal of a coupe.

When Audi launched the original A7 Sportback in 2010, the carmaker was already known for its automotive design, sporty aesthetics and grand elegance. Its dynamic impression is defined by its long bonnet, sporty C-pillars and its sharply dropping rear end.

Now, its revised iteration – with a length of 4.97 meters (16.3 ft) in length – has been further made sportier in terms of looks. The revisions include the Singleframe grille and bumpers as well as headlights and tailpipes. While LED is being employed as standard, it also has Matrix LED headlights -- which could optimally illuminate the road without bothering drivers of oncoming vehicles. The Matrix LED headlights are complemented by dynamic turn signals, which are standard at the rear.

Audi constructed the body of the new A7 Sportback mainly out of aluminum and high-tech steel grades, resulting to a lightweight construction offering optimal comfort in terms of noise. As designed, the new A7 Sportback could accommodate 535 liters (18.9 cu. ft) of cargo, which could further be increased to 1,390 liters (49.1 cu. ft.) by folding down the rear seat backs.

Press Release

Audi bringing new lightweight springs to production models

Audi is reinforcing its leading role in automotive lightweight construction. The company is introducing new, lightweight suspension springs made of glass fiber-reinforced polymer (GFRP) in an upper mid-size model before the end of the year.

The GFRP spring, which Audi developed in collaboration with an Italian supplier, even looks different than a steel spring. It is light green, the fiber strand is thicker than the wire of a steel spring, and it has a slightly larger overall diameter with a lower number of coils. Most importantly, however, it is some 40 percent lighter. Whereas a steel spring for an upper mid-size model weighs nearly 2.7 kilograms (6.0 lb), a GFRP spring with the same properties weighs just approximately 1.6 kilograms (3.5 lb). Together the four GFRP springs thus reduce the weight by roughly 4.4 kilograms (9.7 lb), half of which pertains to the unsprung mass. “The GFRP springs save weight at a crucial location in the chassis system. We are therefore making driving more precise and enhancing vibrational comfort,” said Dr. Ulrich Hackenberg, Member of the Board of Management for Technical Development at AUDI AG.

The core of the springs consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core — which is only a few millimeters in diameter — at alternating angles of plus and minus 45 degrees to the longitudinal axis. These tension and compression plies mutually support one another to optimally absorb the stresses acting on the component. In the last production step, the blank is cured in an oven at temperatures of over 100 degrees Celsius.

The GFRP springs can be precisely tuned to their respective task, and the material exhibits outstanding properties. It does not corrode, even after stone chipping, and is impervious to chemicals such as wheel cleaners. Last but not least, production requires far less energy than the production of steel springs.